What is a bus driver obliged to do once he reaches his final destination?

1. Once the destination stop is announced he is permitted to leave the bus immediately, .without waiting.
2. Correct answer: He should stay on the bus until the last passenger comes off.
3. He may leave the bus, provided that he leaves the air-conditioning on.
4. He should leave the bus straight after shutting off the engine.

WhyAt the final stop the driver stays on the bus until the last passenger has got off. Announcing the stop and leaving is not allowed.